Enthuware

The problem with the code is that since Foo extends FooBase, Foo gets the static method bar() from FooBar(FooBase) in its scope and since Foo also says it implements Bar interface, it needs to have an instance method bar() with the same signature.

misspell?

Fixed.
thank you for your feedback!

this might be silly but just making a mention :

first option has : Add this method in class Foo - public void bar(){ } ;
why is the semicolon there at the end ?

even without ; it will be a wrong option only. but just thought of mentioning.

Extra semicolon is not a problem. It is ignored by the compiler.